共查询到18条相似文献，搜索用时 234 毫秒
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本文通过对目前广泛使用于打桩区位移观测方法的总结，结合某高层建筑基础打桩对周围影响的位移测量实际，提出一种仪器只要一次设站加改正的简便方法，并在施工中得到了应用，取得了很好的效果。 相似文献
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本文采用间接平差原理对码头施工打桩定位测量中典型的正基线上三方面前方交会法进行精度分析，并与常规的两方面前方交会法作适当比较，为打桩这位测量的测设精度提供较为严密的估算方法。 相似文献
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提出了一种基于GPS RTK技术的简易定位模型,阐述了其对平面和高程的定位原理,以实际的定位数据表明其可以实现长江和近岸海域的打桩施工. 相似文献
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码头施工打桩定位测量中常用：直角坐标交会法，前方交会法，角度交会法各种方法的公式中正负号多，同时由于不同的打桩形式：直桩，斜桩，仰打、储打，左扭，右扭，设计标高，控制标高，测点在桩的棱边上，或在桩面中心线上，因此信息量大，不便使用，为此试用方位角来综合处理不同的方法，公式和操作系统，减少输入信息，有利生产，方便教学。 相似文献
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无反射棱镜全站仪打桩定位的方法与数学模型 总被引：2，自引：0，他引：2
探讨如何使用无棱镜反射全站仪对圆桩进行定位的问题,即利用无反射棱镜全站仪定位的功能和快速便捷准确的特点,通过观测桩体上4个点的三维空间坐标,通过一定的数学模型确定桩轴线方位角、倾角、桩顶最低点高程和设计高程面桩中心的坐标。文中研究了计算的数学模型,即通过点与点之间、向量与向量之间的空间关系列立方程组,然后通过一定的变换和非线性方程组的数值解方法得到定位的数据。通过实际观测以及对实际数据处理的程序实现,说明该方法是切实可行的,对近岸打桩以及检验基于GPS-RTK技术的打桩定位系统具有重要意义。 相似文献
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多系统的融合定位可有效提高用户导航定位的连续性、可靠性及定位精度。针对BDS、GPS观测量间存在系统间偏差的实际情况,建立了顾及系统误差的BDS/GPS融合定位模型,即在函数模型中增加附加参数来吸收系统间偏差,构造了新的顾及先验信息的融合定位模型,分析了这种新融合模型的特点及其对定位结果的影响。利用不同品牌接收机在中国不同地域对新的融合模型进行试验,试验结果表明:BDS、GPS观测量存在系统间偏差,且不同接收机的系统间偏差量值并不一样;增加系统参数的融合定位模型能较好地吸收BDS、GPS观测量的系统间偏差的影响,改善其融合导航定位性能;在观测卫星数不足、单系统不能定位的情况下,考虑先验信息的融合定位模型仍能获得较好的定位结果。 相似文献
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The integration of GPS with GLONASS may be considered a major milestone in satellite-based positioning, because it can dramatically
improve the reliability and productivity of said positioning. However, unlike GPS, GLONASS satellites transmit signals at
different frequencies, which result in significant complexity in terms of modeling and ambiguity resolution for integrated
GPS and GLONASS positioning systems. In this paper, a variety of mathematical and stochastic modeling methodologies and ambiguity
resolution strategies are analyzed, and some remaining research challenges are identified. The exercise, of developing mathematical
models and processing methodologies for integrated systems based on more than one satellite system, is a valuable one as it
identified crucial issues concerned with the combination of any two or more microwave positioning systems, be they satellite-based
or terrestrial. Hence these are experiences that can be applied to future projects that might integrate GPS with Galileo,
or GLONASS and Galileo, or all three. ? 2001 John Wiley & Sons, Inc. 相似文献
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Double-differenced (DD) ambiguities between overlapping frequencies from different GNSS constellations can be fixed to integers if the associated differential inter-system biases (DISBs) are well known. In this case, only one common pivot satellite is sufficient for inter-system ambiguity resolution. This will be beneficial to ambiguity resolution (AR) and real-time kinematic (RTK) positioning especially when only a few satellites are observed. However, for GPS and current operational BDS-2, there are no overlapping frequencies. Due to the influence of different frequencies, the inter-system DD ambiguities still cannot be fixed to integers even if the DISBs are precisely known. In this contribution, we present an inter-system differencing model for combined GPS and BDS single-frequency RTK positioning through real-time estimation of DISBs. The stability of GPS L1 and BDS B1 DISBs is analyzed with different receiver types. Along with parameterization and using the short-term stability of DISBs, the DD ambiguities between GPS and BDS pivot satellites and the between-receiver single-difference ambiguity of the GPS pivot satellite can be estimable jointly with the differential phase DISB term from epoch to epoch. Then the inter-system differencing model can benefit from the near time-constant DISB parameters and thus has better multi-epoch positioning performance than the classical intra-system differencing model. The combined GPS and BDS single-frequency RTK positioning performance is evaluated with various simulated satellite visibilities. It will be shown that compared with the classical intra-system differencing model, the proposed model can effectively improve the positioning accuracy and reliability, especially for severely obstructed situations with only a few satellites observed. 相似文献
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随着全球四大卫星导航系统格局的成型,卫星定位系统已从单系统模式发展为如今多系统、多频率融合定位、交互操作的模式。在分析多系统精密单点定位模型及各误差项处理策略的基础上,利用RTKLIB进行GPS,GLONASS,GALILEO,BDS多系统融合精密单点定位试验,并分析其动/静态定位性能。实验结果表明:在单系统空间几何构型较差的情况下,多系统融合精密单点定位较单GPS定位精度可提高20%~40%,收敛时间可缩短35%~50%;在截止高度角超过40°的情况下,单系统会因可见卫星数量不足而无法完成连续定位,而多系统仍能实现高精度的连续定位。这在城区、山区或卫星遮蔽较严重的不利环境中有重要的利用价值。 相似文献
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Stochastic assessment of GPS carrier phase measurements for precise static relative positioning 总被引：17，自引：11，他引：17
Global positioning system (GPS) carrier phase measurements are used in all precise static relative positioning applications.
The GPS carrier phase measurements are generally processed using the least-squares method, for which both functional and stochastic
models need to be carefully defined. Whilst the functional model for precise GPS positioning is well documented in the literature,
realistic stochastic modelling for the GPS carrier phase measurements is still both a controversial topic and a difficult
task to accomplish in practice. The common practice of assuming that the raw GPS measurements are statistically independent
in space and time, and have the same accuracy, is certainly not realistic. Any mis-specification in the stochastic model will
inevitably lead to unreliable positioning results. A stochastic assessment procedure has been developed to take into account
the heteroscedastic, space- and time-correlated error structure of the GPS measurements. Test results indicate that the reliability
of the estimated positioning results is improved by applying the developed stochastic assessment procedure. In addition, the
quality of ambiguity resolution can be more realistically evaluated.
Received: 13 February 2001 / Accepted: 3 September 2001 相似文献
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The Global Positioning System (GPS), in addition to providing precise navigation and positioning information, produces precise
time and frequency measurements. These measurements result from the atomic clocks in the GPS satellites, which are closely
coupled to Universal Coordinated Time as maintained by the U. S. Naval Observatory [UTC(USNO)]. The application of these measurements
to timekeeping and other systems requiring precise time and frequency is distinct from the navigation/positioning mission.
This article will describe the differences in application of GPS to time and frequency uses. These uses will be described
in the major areas of timekeeping; stationary uses, such as communications networking; and mobile use for aircraft and shipboard
applications. The major considerations in application and operation with precise and less-capable oscilators will be described.
Examples and data will be presented to illustrate the applications. ? 1999 John Wiley & Sons, Inc. 相似文献